Thread (11 messages) 11 messages, 3 authors, 2021-06-25

Re: [PATCH v5 for-next 0/3] IB/core: Obtaining subnet_prefix from cache in

From: Jason Gunthorpe <jgg@nvidia.com>
Date: 2021-06-21 23:53:04
Also in: lkml

On Wed, Jun 16, 2021 at 09:15:06PM +0530, Anand Khoje wrote:
This v5 patch series is used to read the port_attribute subnet_prefix
from a valid cache entry instead of having to call
device->ops.query_gid() in Infiniband link-layer devices. This requires
addition of a flag used to check that the cache entry is initialized and
that a valid value is being read.

1. Removed the port validity check from ib_get_cached_subnet_prefix.
This check was not useful as the port_num is always valid.

2. Shuffled locks pkey_lost_lock and netdev_lock in struct ib_port_data.
This was done as output of pahole showed two 4-byte holes in the
structure ib_port_data after pkey_list_lock and netdev_lock. Moving
netdev_lock shaved off 8 bytes from the structure.

3. Added a flag to struct ib_port_data. This is used to validate the
status of cached subnet_prefix. This valid cache entry of subnet_prefix
is used in function __ib_query_port().
This allows the utilization of the cache entry and hence avoids a call
into device->ops.query_gid(). We also ensure that in the event of a
cache update, the value for subnet_prefix gets read from the newly updated
GID cache and not via ib_query_port(), so that we do not end up reading a
stale cache value.

Anand Khoje (3):
  IB/core: Removed port validity check from ib_get_cached_subnet_prefix
  IB/core: Shuffle locks in ib_port_data to save memory
I took these two, thanks

Jason
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